Serial printer with rotating interposer and plural hammers

ABSTRACT

A serial printer is provided having a movable typecarrying member, a movable carriage bearing a part of printing hammers having heads partially superimposed and an interposer member having elements to which is imparted motion correlated to the print carriage and in the opposite direction. Printing is effected by cooperation of the print hammers and the typecarrying member, through the interposer.

United States Patent 91 Bossi [4 1 Sept. 25, 1973 SERIAL PRINTER WITH ROTATING INTERPOSER AND PLURAL HAMMERS [75] Inventor: Oscar Bossi, Milano, ltaly [73] Assignee: Honeywell Information Systems Italia, Milan, Italy 22 Filed: July 12, 1971 21 Appl. No.: 161,678

[30] Foreign Application Priority Data July 14, 1970 ltaly 27390 A/70 [52] US. Cl 197/53, 101/93 C, 197/18, 197/49 [51] Int. Cl B41] l/32 [58] Field of Search 197/18, 53, 49; v 101/93 C [56] References Cited UNITED STATES PATENTS 3,012,499 12/1961 Amada 101/93 C 3,371,766 3/1968 Staller 197/53 3,388,782 6/1968 Schwend 197/49 3,542,182 11/1970 Langenberger 197/18 3,565,230 2/1971 Webberley 197/49 3,643,774 2/1972 Kondur 197/49 X 3,651,915 3/1972 Folkens 197/53 3,651,916 3/1972 Becchi 197/18 X Primary Examiner-Edgar S. Burr Attorney--George V. Eltgroth et al.

[ 5 7 ABSTRACT A serial printer is provided having a movable typecarrying member, a movable carriage bearing a part of printing hammers having heads partially superimposed and an interposer member having elements to which is imparted motion correlated to the print carriage and in the opposite direction. Printing is effected by coopera tion of the print hammers and the typecarrying member, through the interposer.

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SERIAL PRINTER WITH ROTATING INTERPOSER AND PLURAL HAMMERS BACKGROUND OF THE INVENTION The present invention relates to high speed impact printers utilized in data processing systems, and particularly to on-the-fly serial printers.

Many different constructive arrangements have been adopted for these printers, so that they may be distinguished in synchronous or asynchronous, front printing or back printing serial printers.

In any case such printers comprise; a typecarrying member kept in continuous motion for bringing in succession all characters of a character set in registration with each predetermined print position; a printing member or printing hammer, actuated at the proper instants, that is, when the character which has to print is in the proper printing position; and a printing member or printing hammer, actuated at the proper instants, that is, when the character which has to print is in the proper printing position, and a carriage member for moving the printing hammer and, in most cases, also the typecarrying member, along the line of print.

It is known that the required characteristics for such printers are a high printing speed, and a fine quality of printing, and that these characteristics are, in a sense, mutually incompatible.

It is also known that, in order to obtain betterperformances from the printer, it is suitable to arrange the characters on the typecarrying member as mutually close as possible so that, for a given time needed for the typecarrying member to bring all characters in front of a given print position, the effective speed of each character while passing through said position may be as low as possible.

However, the packing of the characters as mutually close as would be permitted by their dimensions is usually not possible due to other reasons, such as the width of the printing hammer, which in some printers should extend substantially over two adjacent print positions, but should be prevented from simultaneously printing two characters; the danger of mechanical interference, the restoration time of the printing hammer, and others.

Some attempts to obviate these disadvantages have been made by introducing an intermediate member in the printing operation, but the mechanical devices employed for this purpose have poor'reliability, are limited to peculiar constructive arrangements, and do not completely solve the problem.

An object of the invention therefore is to increase the packing density of the characters borne by the typecarrying member, thus improving the quality of the printing and the performance of the printer.

SUMMARY OF THE INVENTION The aforesaid object is attained, according to the invention, by the use of an intermediate member interposed between printing hammer and type-carrying member, such intermediate member, called henceforth an interposer, being associated with a pair of partially superimposed printing hammers.

BRIEF DESCRIPTION OF THE DRAWINGS accompanying drawings, wherein:

FIG. 1 is a perspective simplified view of an on-thefly serial printer according to the state of the art;

FIG. 2 is a perspective view of a portion of a printer according to the invention, showing only the parts concerned therewith;

FIG. 3 is a schematic block diagram of a control de vice for a synchronous serial printer according to the invention;

FIG. 4 is a schematic block diagram of a control device for an asynchronous serial printer according to the invention;

FIG. 5 illustrates a first alternative form of the mechanical device for transmitting the motion to the interposer;

FIG. 6 illustrates a second alternative form of the said mechanical device;

FIG. 7 illustrates a third alternative form of the said mechanical device; and

FIG. 8a and FIG. 8b are respectively a partial plan view and a partial front elevation view illustrating an alternative form of the interposer and the related arrangement of the associated hammers.

DESCRIPTION OF A PRIOR ART PRINTER FIG. I shows a synchronous serial printer of the known type. It comprises a main frame 1 which accommodates a print carriage 2, slidable along prismatic rotatable guiding bars 3 and 4. The printing carriage 2 bears a printing hammer 5 actuated by an electromagnet 6 and a type-carrying member 7 comprising a plurality of radial flexible tongues 8. The characters are arranged in relief each one at the outer extremity of a tongue. The typecarrying member 7 is kept in continuous uniform rotation, for instance through operation of the bevel gear pair 9 and the prismatic bar 4, by a motor means 10. A coding or timing disk I l is secured to the motor shaft. It cooperates with pick-up means 12 and 13 (which may be of the optic, magnetic, or other type) for generating suitable pulses for identifying the characters and timing the operation. Due to the rotation of the typecarrying member 7, the different characters keep passing in sequence between the printing hammer 5 and an interposer 24 on one side, an inkribbon 14, a print receiving medium 15 and a platen member 16 on the other side, in such a way that, by energizing the electromagnet 6 at a proper instant defined by the timing device, the desired character is printed on the print receiving medium.

The printing is not accomplished due to the direct action of the head of the hammer 5 on the selected tongue 8, but through the interposer 24, pivoted on a pin 25 fixed to the print carriage 2, and having an extension arm provided with a roller 27 cooperating with a cam 26. The cam 26 is secured to the shaft of the rotating typecarrying member 7 and imparts by its rotation an alternate motion, along the direction of the print line, to the tip of the interposer 24 which thus remains interposed between the hammer 5 and the typecarrying tongue 8. The reason for this arrangement will be explained hereafter.

Besides rotating the typecarrying member 7 the motor means 10 also causes rotation of the screw 18, through the gear pair 17. The screw 18 has a pitch equal to the spacing between two consecutive print positions, that is the print pitch, or a multiple thereof. A tooth 19, mounted on the print carriage 2, generally engages the screw 18 in such a way, that by turning the screw 18, the print carriage 2 is moved along the print line with uniform speed. The velocity ratios of gear pairs 9 and 17 is such, that for each complete turn of the typecarrying member 7, the print carriage 2 advances the space of a print pitch.

An electromagnet with a rotating armature 20, may be provided to rotate the prismatic bar 3 in response to a carriage return command to disengage the tooth 19 from the screw 18, permitting a spring 21 to move the carriage 2 back into the start position, by means of a cable 22 and a pulley 23. Other devices, not shown, provide for the advancing of the ink-ribbon and for the line feed of the print receiving medium.

Rather than dwell upon these details, it is now conve nient to consider the mechanics of the on-the-fly printing operation, for a better understanding of the invention. i

As stated before, the print carriage 2 moves at uniform speed from each print position to a subsequent one, in synchronism with the rotation of the typecarrying member 7. The firing of the printing hammer must take place when the tongue 8 bearing the desired character is in the proper printing position. This means that the firing command is given when the carriage 2 is in a predetermined position comprised of a distance equal to a print pitch. The hammer 5 is secured to the carriage 2 and therefore it is moving with respect to the print positions, which stand still; therefore it should have a width larger than a whole print pitch to ensure in any case that the tongue 8 is pushed against the print receiving medium 15. In the absence of the interposer 24, it would be necessary to further mutually space the typecarrying tongues 8 to avoid printing two characters at a time.

The presence of the interposer 24 may dispose of the above problems, but it has to be moved backward with a velocity equal and opposite to the carriage velocity, so that the sum of the two velocities in null; that is, the interposer 24 should remain constantly in registration with a print position. After each complete turn of the typecarrying member 7, the backward motion of the interposer 24 should be stopped, and brought into registration with the consecutive print position, as soon as possible. At best, this operation should be instantaneous.

Cam 25 provides for this motion, which however takes a short, but finite interval of time; this is a dead" time, during which no printing may take place. This interval is, for example, about 4-6 milliseconds and extends between the initial time and the final time of the period allowed for the printing of the character set.

In other words, assuming that the set of characters to be printed is the alphabetical set comprising all letters from A to Z, in alphabetical order, these characters are not distributed uniformly at the periphery of the typecarrying member 7, but there is a void sector corresponding to said dead time interval. This sector is also necessary for permitting the hammer 5, which has been actuated for printing, for example the character Z, to be restored at its start position and to be subsequently actuated for printing the character A in the following print position. This would not be possible if the character A were in registration with the following print position at the same time or immediately after the presence of the character Z in registration with the preceding print position.

The rotation period of the typecarrying member 7 may be, for example, 20 milliseconds. Therefore, the need for a void sector corresponding to a time interval of 4 to 6 milliseconds reduces the printing speed up to about 2025 percent of the speed which could; be reached if such inconvenience were removed. In addition, the necessity of moving the interposer in a jerky manner, subjects the same to relevant mechanical stresses which jeopardize the reliability of the device.

These inadequacies of the prior art are removed, according to the present invention, by employing a rotating interposer having a plurality of arms, and associated with two printing hammers, selectively controlled.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 2 shows, in a schematic form limited to the parts essentially needed for the understanding of the invention, a serial on-the-fly printer of the synchronous type, arranged in accordance to the present invention. As portions of the more general structure of the printer shown in FIG. 2 are similar to those already described with reference to FIG. 1, the corresponding parts are to be indicated by the same reference numerals.

It may be noted that, in the printer of FIG. 2, unlike that of FIG. 1, there are two printing hammers 31 and 32 respectively controlled by electromagnets 33 and 34. The hammers 31 and 32 are partially superimposed and are somewhat staggered in direction of the print line. They may act on the tongues 8 of the daisy-shaped typcarrying member, through an interposer member which is also daisy-shaped, comprising a plurality of flexible blades 36, which may rotate freely on the same shaft as the typecarrying member.

The interposer member is integral to a gear wheel 37 which engages with a rack 38 which is arranged in parallel relation to the print line and fixed to the main frame of the printer. The rack 38 is located in a lower and backward position with respect to the print line, in order to allow the typecarrying element and the interposer to pass between the print receiving medium and the rack and to jut out above the rack. However, for reasons to be explained hereinafter, the ratio of the diameters of the interposer to that of the gear wheel 37 should not substantially vary from unity.

The ink-ribbon 14 that is in correspondence with the print positions of the line which have already been printed, is displaced from the print line by means of guiding pegs 39 and 40 located to the left to the typecarrying member, thus obtaining almost immediate visibility of the printed text.

The peripheral portions of the interposer blades 36 are twisted at a right angle to become perpendicular to the plane of the print, thus presenting a very reduced width in the direction of the print line. When the carriage advances along the print line the gear wheel 37, engaged by the rack 38, lets the interposer turn anticlockwise. The resultant of the two motions, that is, the one of translation of the carriage, and the one of rotation of the interposer, is a very small displacement in the direction of the print line, of the tips 41 of the blades 36 interposed between the hammers and the typecarrying member, this displacement being associated to a small rotation angle.

In other words, the tip 41 remains substantially in registration on a prefixed print position during the time in which the print carriage is moved from a print position to the immediately following one. As the carriage continues to move, then the following tip 42 comes into registration with the immediately following print position.

As the carriage moves along the print line, there will always be a tip 41 of a blade 36 of the interposer which will be in registration with the print position which is to receive the print, and this is brought about without sustaining alternate motions and without having dead time intervals The pitch of the blades 36 of the interposer is slightly larger than the print pitch, because, as has been pointed out, the gear wheel 37 has a diameter slightly smaller than the diameter of the interposer; in consequence, the peripheral tips 41 of the blades 36 of the interposer are subject to a negative shift with respect to the print position, which, however, may be restrained to within reduced and acceptable limits.

The use of two print hammers 31 and 32 selectively controlled, serves to prevent double printing, and, at the same time, together with the rotating interposer, does away with the need of leaving a void sector in the typecarrying member, and thereby allows its maximal close packing. in fact, the translation motion of the print carriage from a print position to the following one, may ideally be subdivided into two half-periods. During the first halfiperiod only the firing of a hammer, for example hammer 31, is allowed, during the second semiperiod only the firing of the other hammer, that is hammer 32, is allowed.

The start of a cycle for scanning the characters of the typecarrying member, in order to control the printing of the desired character on a predetermined print position is, of course, made to coincide with the initial time of the travel of the carriage from a print position to the following one. Therefore, the two printing hammers should have a width sufficient for acting on the interposer for half a print pitch each. As the pitch of the blades 36 of the interposer is equal to or slightly larger than a print pitch, the possibility of double printing is eliminated.

in addition, the small width of the tips 41 of the interposer blades 36, and the fact that they are practically in registration with the center line of the print position eliminates any danger of mutual interference, even if the characters are as closely packed as pennitted by their geometrical dimensions.

Considering now the consecutive printing of two characters in two consecutive print positions, and assuming that the first character to be printed is the letter Z and the following character is the letter A, the first printing operation will take place when the print carriage is completing the second half-period of travel, and therefore will occur by the action of the hammer 32, whereas the second printing operation will take place when the print carriage is initiating the first halfperiod of travel corresponding to the subsequent print pitch, and therefore will occur by the action of hammer 31. In any case, each of the hammers 31 and 32 will have at its disposal a minimum recovery time equal to the half-period of rotation of the typecarrying member. Practically, depending on the print speed and the dimensions of the typecarryin g member, such half-period may comprise between and 40 milliseconds, and is therefore sufficient to permit the recovery of the printing hammers 31 and 32, without having to provide void sectors on the typecarrying member.

FIG. 3 shows the logical block diagram of a circuit particularly suitable for controlling the printing hammers 31 and 32 in a serial synchronous printer of the described type.

A timing disk 61 rotates synchronically with the typecarrying member and in correlation with the motion of the print carriage. The disk 61 is provided at its periphery with a succession of notches, each one corresponding to a character position of the typecarrying member, which in the considered example is assumed to have 64 characters.

A pick-up device 62 delivers, in correspondence with the passage of each notch in front of a reading head 63, an electrical pulse which is applied to input lead 64 of a binary counter 65. The counter 65 comprises for example 6 bistable elements and may count from 0 to 63.

Six output leads 66 of the counter send out a binary code whereby each code combination is representative of the character to be printed. These output leads 66 are applied to the input leads of a comparing circuit 69, having other input leads 70 to which the code combination representative of the character to be printed is applied. When the code combination of the character which is in print position coincides with the code combination of the character to be printed, the comparing circuit 69 provides a print command signal to the output lead 71.

According to the invention, this command is selectively applied to one of the two hammers 31, 32 provided on the printer, the selection being made in the following described manner.

The most significant output of the counter 65 is connected to a lead 67, and therefore directly to a first input lead of a logical AND gate 72, and through an inverter 74, to a first input of an AND gate 73. The output lead 71 of the comparing circuit is connected to the second input of each of these gates 72, 73. The output leads of the AND gates '72 and 73 control respectively the actuating circuits 75 and 76 of the hammers 31, 32.

When the counter sends out at its output leads a code combination representative of a decimal number located between 0 and 31 inclusive, the lead 67 is at binary level 0 and the AND gate 72 is inhibited. On the other hand the AND gate 73 is enabled. Therefore, if the character to be printed has a code combination located between decimal numbers 0 and 31 inclusive, the printing command is transferred through the AND gate 73 to he actuating circuit 76.

When the counter 65 gives out a binary code combination representative of a decimal number located between 32 and 63 inclusive, the lead 67 is at binary level 1 and therefore AND gate 72 is enabled and AND gate 73 is inhibited. Therefore, if the character to be printed has a code combination located between decimal numbers 32 and 63, inclusive, the print command signal is transferred through AND gate '72 to the actuating circuit 75.

As a consequence of the selective control of the two printing hammers according to the character code combination, and due to the one-to-one correspondence between positions of the print carriage and of the typecarrying member, during a first half of the travel of the print carriage from one print position to the following one, a first hammer is permitted to be fired and during the second half of the travel the second hammer is permitted to be fired.

It must be noted that the invention is applicable also to a printer of the asynchronous type, whereby there is no one-to-one correspondence between positions of the typecarrying member and print carriage. A printer of this type is described in the Italian Pat. 885,844. In this instance the selective control of the two hammers is preferably accomplished by direct control from the position of the print carriage.

FIG. 4 illustrates in schematical block diagram form a control device to this type.

The timing disk 61, with the reading head 63 of the pick-up device 62, the counter 65 and the comparing circuit 69, as already stated, provide for generating the print command signal, on lead 71. The selection of the printing hammer is made in the following manner.

A second timing device 81 is associated with the advancement mechanism of the print carriage, and, in cooperation with a pick-up device 82 provides a pulse, at an output lead 83 thereof, each time the print carriage reaches or goes beyond a print position and an intermediate position, for example the middle position between two print positions. These pulses are applied, through the output lead 83, to the input of a flip-flop 84, which changes its state at the reception of each pulse. Two binary values l and which enable or inhibit alternativey the AND gates 87 and 88 are therefore present to the output leads 85 and 86 alternatively for the duration of a half pitch. The print command signal is therefore selectively transferred through AND gates 87 and 88 to one of the circuits 89 and 90 actuating the print hammers.

In the preceding description reference has been made to preferred embodiments of the invention in serial printers using a daisy-shaped type-carrying member. However, it is self evident that many modifications may be made to the constructive arrangement described, without departing from the spirit and scope of the invention. In particular some different constructive arrangments which may be of interest for controlling the motion of the rotating interposer, are hereby described.

FIG. shows a rack-and-gear pair device substantially similar to the device illustrated in FIG. 2.

A rack 101 is rigidly fixed to the printer frame, not shown, by screws 102. The screws pass through elongated slots in the rack, to allow for adjusting its position. On the print carriage are mounted: a first gear wheel 103 engaged by the rack 101, a pinion 104 secured to a shaft 105 of the gear 103, and a second gear wheel 106 engaged by the pinion 104. The gear wheel 106 is secured to the shaft of the rotating interposer 107 and the gear wheel 106 is secured to the shaft of the rotating interposer 107 and the gear ratios of the device may be so chosen, such that the displacement of the carriage by a print pitch causes a equal displacement in the opposite direction of the tip of a rotating interposer. The device is more complex than the one shown in FIG. 2, but it provides a larger number of design parameters, and it is possible to dimension the various parts according to the various operating and space requirements.

FIG. 6 shows a different arrangement whereby the motion of the interposer is controlled by a rotating bar which provides for the motion of the typecarrying member.

A bar 111 rotates a bevel gear wheel 112 and may glide axially along the said bar. The bevel gear wheel 1 12 transmits rotational motion to a typecarrying member 115 by means of a bevel gear wheel 114, while the worm screw rotates an interposer 116 through gear wheels 117, 118 and 119. Also, in this instance the gear ratios are so chosen that for a displacement of the carriage equal to a print pitch, the tip of the interposer moves in the opposite direction by the same amount.

FIG. 7 illustrates a further arrangement whereby the interposer motion is controlled by the same motive members which cause the motion of the typecarrying member. A toothed belt 120 is kept in motion by at least one of a pair of pulleys 121 and 122 and imparts a rotative motion to a pair of pulleys 123 and 124 mounted on the print carriage. Pulley 123 is secured to a shaft 125 of a typecarrying member 126 and maintains the same in rotation. The typecarrying member 126 is only partially shown in FIG. 7.

The pulley 124 is secured to an auxiliary shaft 127 to which is also secured a bevel gear wheel 128. This wheel 128 engages a bevel gear wheel 129, which, by means of a shaft 130, rotates a worm screw 131. This in turn rotates a gear wheel 132 secured to a hollow shaft 133 coaxial to the shaft 125. An interposer 134, only partially shown, is secured to the same shaft 133. The gear ratios are so chosen, that the interposer 134 rotates slowly in such a way, that in correspondence of the print line, the tips of its blades acquire a motion equal and opposite to the carriage motion.

It is convenient, in addition, to remark that, in the instance of synchronous printers, of the described type, provided with two printing hammers, the use of two hammers provides a further advantage, that of having available two printing members with different print energies.

It is known that, in order to obtain a fine quality of print, the printing should be efiected with an energy that, at least in a first approximation, should be proportional to the dimension and the surface of the character to be printed. Thus, for printing a period, a comma, a semicolon, an asterisk and similar signs, a lower energy is needed than for printing an alphabetic character, and more energy is needed for a capital letter character than for a lower case character.

With reference to FIG. 2, it may be seen that it is possible to arrange the characters on the typecarrying member, in such a way, that they are distributed in two portions of the same, according to their dimensions and surfaces. For each one of the two portions, the printing is selectively made by one of the two hammers, therefore, different energizing circuits may be provided for the two hammers in order to have two different energy levels.

A last and most important remark must also be made. In the prior description, constructive arrangements have been illustrated, in which two printing hammers may act selectively on the same part of an interposer, that is, on the tip of the same blade of the interposer. The hammers have suitably a width slightly larger than half a print pitch, and are conveniently mutually staggered. However, it is also possible to use two superimposed hammers having a width substantially equal to two print positions and alternatively cooperating with difierent, mutually alternate, blade tips. FIGS. 80 and 8b schematically illustrate such arrangement.

FIG. 8a is a front elevation view of a portion of a rotating interposer, comprising three blades 140, 141, 142.

The tip of each blade, which corresponds to a print position, is provided, in a directional normal to the printing plane, with a relief alternatively located at a different distance from the center of the rotating interposer. In other words, the said reliefs are arranged alternatively on two different orders.

For instance, in FIG. 8a, the relief 143 is located on the outer, or higher order, and the reliefs 144, 142 are located in the inner, or lower order. This may also be seen in FIG. 8b which shows a sectional plan view of the tips of the blades. The printing hammers 146 and 147, mutually superimposed and in registration with the said two orders, are located in front of the reliefs. Also, the width of the hammers is substantially equal to two print positions.

During the travel of the print carriage on which the hammers and the interposer are mounted, the tips of the blades remain in registration with the different print positions, and with each of these is associated a relief, respectively on a first or on a second order according to whether the print position is on an even-number or an odd-number location. The first hammer is fired to obtain the printing for instance on the even-number positions and the second hammer is fired for printing on the odd-number positions. Each hammer can cooperate only with the reliefs of a given order; therefore even having a width equal to two print positons, no double printing may take place. On the other hand the fact that each print hammer covers two print pitches permits printing in a prefixed print position even if the carriage moves along a whole print pitch.

The alternative firing of the two print hammers may be controlled by logical circuits, associated to the devices which control the advancement of the carriage and which do not offer peculiar conceptual or practical difficulties. Substantially such logical circuitry is similar to that described with reference to FIG. 4 and therefore its description is ommited.

What is claimed is:

l. A serial on-the-fly printer, comprising a typecarrying member in continuous motion for bringing into print position in succession the characters of a character set, a print carriage movable along the print line, for occupying in succession all possible positions along a print line, a printing member mounted on said print carriage, said printing member comprising two printing hammers having at least partially superimposed printing heads, an interposer member mounted on said print carriage and havingvariable portions interposable in succession between said type-carrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said type-carrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

2. A serial on-the-fly printer, comprising a print carriage movable along the print line, for occupying in succession all the possible positions along the print line, a typecarrying member in continuous motion for bringing into print position in succession every character of a character set, mounted on said print carriage; a printing member mounted on said print carriage, said printing member-comprising two printing hammers having at least partially superimposed printing heads, an interposer member mounted on said print carraige and having variable portions interposable in succession between said typecarrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

3. The serial printer of claim 2, whereby said typecarrying member comprises a rotating daisy-shaped assembly of flexible tongues, each tongue of said daisyshaped assembly bearing at its free extremity a character of the said character set. i

4. The serial printer of claim 3, wherein said interposer member comprises a rotatable daisy-shaped assembly formed of flexible blades, having said variable portions at the ends thereof, and said assembly being disposed coaxial to said typecarrying member.

5. Serial on-the-fly printer comprislng a typecarrying member in continuous motion for bringing into print position in succession the characters of a character set, a print carriage movable along the print line, for occupying in succession all possible positions along the print line, a printing member mounted on said print carriage, said printing member comprising two printing hammers having partially superimposed printing heads mutually staggered in the direction of the print line, an interposer member mounted on said print carriage and having variable portions interposable in succession between said typecarrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

6. Serial on-the-fly printer, comprising a print carriage movable along the print line, for occupying in succession all the possible positions along the print line, a typecarrying member in continuous motion for bringing into print position in succession every character of a character set, mounted on said print carriage; a printing member mounted on said print carriage, said printing member comprising two printing hammers having partially superimposed printing heads mutually staggered in the direction of the print line, an interposer member mounted on said print carriage and having variable portions interposable in succession between said typecarrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

7. Serial on-the-fly printer comprising a'typecarrying member in continuous motion for bringing into print position in succession every character of a character set;

a print carriage movable along the print line, for occupying in succession all possible positions along the print line;

a-printing member mounted on said print carriage and comprising a first and a second printing hammer having printing heads superimposed on a first and a second level, said printing heads having a width sufiicient to span two print positions;

an interposer member, mounted on said print carriage, and having variable portions interposable in succession between said typecarrying member and said printing member, said variable portions being alternatively provided with reliefs in correspondence of said first and of said second level, for cooperating alternatively with the printing heads of said first and said second printing hammers,

means for activating said interposer member for imparting to the portion of said interposed member interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

8. Serial on-the-fly printer, comprising a print carriage movable along the print line, for occupying in succession all the possible positions along the print line;

a typecarrying member in continuous motion for bringing into print position in succession every character of a character set, mounted on said print carriage;

a printing member mounted on said print carriage and comprising a first and a second printing hammer having printing heads superimposed on a first and a second level, said printing heads having a width sufficient to span two print positions;

an interposer member, mounted on said print carriage, and having variable portions interposable in succession between said typecarrying member and said printing member, said variable portions being alternatively provided with reliefs in correspondence of said first and of said second level, for cooperating alternatively with the printing heads of said first and said second printing hammers;

means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto, for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

9. A serial printer comprising: typecarrying means movable adjacent a plurality of print positions in a print line, carriage means movable along a line parallel to the print line, printing means disposed on said carriage and comprising at least two printing hammers partially superimposed, interposer means comprising a plurality of portions interposable in succession between said typecarrying means and said printing hammers, and means for imparting a motion to said interposer portion disposed between said typecarrying means and said printing hammer which motion is correlated to movement of said carriage which is in the opposite direction, to said carriage movement for maintaining said interposer portion in a substantially fixed position in registration with a predetermined print position during its interposed interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.

UNITED STATES PATENT OFFICE Page 1 of 3 CERTIFICATE OF CORRECTION Patent 3,760,925 Dated September 25, 1973 Inventor(s) Oscar Bossi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

, In the Specification Column 1, lines 18-21 delete "and a printing member or printing hammer, actuated at the proper instants, that is, when the character which has to print is in the proper printing position,".

v Column 3, line 39 I delete "in" and substitute is-.

Column 4, line BO delete "typcarrying" and substitute -typecarrying---.

. Column 6, line 46 delete "he" and substitute --the-.

Column 7, line 7 delete "to" and substitute -of-- .lines' 49-50 delete "and the gear wheel 106 is secured to the shaft of the rotating interposer Column 9, line 35. delete "ommited? and substitute omitted-.

In the Claims Claim 1, column 9, line 57 delete "metnioned'f and substitute --mentioned--.

Claim 2, column 10, line 13 delete "metnioned" and substitute -mentioned--.

FORM po"oso I USCOMM-DC 90376-P69 V ".5v GDYIRNHINT PRINTING OFFICE 2 ".9 0-35-33,

ILUNITED STATES PATENT OFFICE Page 2 of 3 CERTIFICATE OF CORRECTION Patent No. 3, 760,925 Dated September 25, 1973 Inve Oscar BOSSl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim- 5, column 10, line 27 delete "comprislng" and substitute 1 --comprising-.

column 10, line 47 delete "metnioned" and substitute -mentioned--.

Claim 6, column 11, line 5 delete "metnionedY' and substitute 1 mentioned-.

Claim 7, column 11, line 38 delete "metnioned" and substitute -mentioned-.

- Claim 8, column 12, line 23 delete "metnioned" and substitute I -mentioned--.

' Claim 9 column, 12,- line 3 9 after "carriage" insert -and--.

column 12, line 44 delete "metnioned" and substitute --mentioned-.q

After Claim 9, column 12, line 47 add the following claims:

Claim 10 The serial printer of Claim 9 wherein said typecarrying means comprises a rotating assembly of flexible tongues each tongue having disposed at its free extremity a character of a characterset.

Claim 11- The serial printer of Claim lO wherein said interposer means comprises a rotatable assembly of flexible blades having said portions disposed at the ends thereof, said assembly being located coaxial with said typecarrying means FORM Po-wso (10-69) v a USCOMWDC scans-poo U.Sv GOVERNIEN'I PRINTING OFFICE "l9 0-358-884.

UNITED STATES PATENT OFFICE Page 3 of 3 CERTIFICATE OF CORRECTION Pat n 3,760,925 Dated- September 25. 1973 Inventor-(s) Oscar Bossi It is certified that error appears in the above-identified patent and'that said Letters Patent are hereby corrected as shown below:

Claim 12 The serial printer of Claim -9 wherein said printing heads are superimposed as set forth on a first and a second level each head having a width substantially equal to two print positions, and wherein said interposer portions are provided with reliefs in correspondence with said first and second levels for cooperating alternatively with said two printing heads.

Signed and'sealed this 16th day oi July 1974.

' (SE L) Attest:

MCCOY n. GIBSON, JR. c. MARSHALL DANN Attestlng Officer I Commissioner" of Patents F 0-69) V I uscoMM-oc 60376-P69 1 Us GOVERNMENT 'IINTING OFFICE 1 I... 0'-36-l3l 

1. A serial on-the-fly printer, comprising a type-carrying member in continuous motion for bringing into print position in succession the characters of a character set, a print carriage movable along the print line, for occupying in succession all possible positions along a print line, a printing member mounted on said print carriage, said printing member comprising two printing hammers having at least partially superimposed printing heads, an interposer member mounted on said print carriage and having variable portions interposable in succession between said type-carrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said type-carrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 2. A serial on-the-fly printer, comprising a print carriage movable along the print line, for occupying in succession all the possible positions along the print line, a typecarrying member in continuous motion for bringing into print position in succession every character of a character set, mounted on said print carriage; a printing member mounted on said print carriage, said printing member comprising two printing hammers having at least partially superimposed printing heads, an interposer member mounted on said print carraige and having variable pOrtions interposable in succession between said typecarrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 3. The serial printer of claim 2, whereby said typecarrying member comprises a rotating daisy-shaped assembly of flexible tongues, each tongue of said daisy-shaped assembly bearing at its free extremity a character of the said character set.
 4. The serial printer of claim 3, wherein said interposer member comprises a rotatable daisy-shaped assembly formed of flexible blades, having said variable portions at the ends thereof, and said assembly being disposed coaxial to said type-carrying member.
 5. Serial on-the-fly printer compris1ng a typecarrying member in continuous motion for bringing into print position in succession the characters of a character set, a print carriage movable along the print line, for occupying in succession all possible positions along the print line, a printing member mounted on said print carriage, said printing member comprising two printing hammers having partially superimposed printing heads mutually staggered in the direction of the print line, an interposer member mounted on said print carriage and having variable portions interposable in succession between said typecarrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last metnioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 6. Serial on-the-fly printer, comprising a print carriage movable along the print line, for occupying in succession all the possible positions along the print line, a typecarrying member in continuous motion for bringing into print position in succession every character of a character set, mounted on said print carriage; a printing member mounted on said print carriage, said printing member comprising two printing hammers having partially superimposed printing heads mutually staggered in the direction of the print line, an interposer member mounted on said print carriage and having variable portions interposable in succession between said typecarrying member and said printing member, means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last mentioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 7. Serial on-the-fly printer comprising a typecarrying member in continuous motion for bringing into print position in succession every character of a character set; a print carriage movable along the print line, for occupying in succession all possible Positions along the print line; a printing member mounted on said print carriage and comprising a first and a second printing hammer having printing heads superimposed on a first and a second level, said printing heads having a width sufficient to span two print positions; an interposer member, mounted on said print carriage, and having variable portions interposable in succession between said typecarrying member and said printing member, said variable portions being alternatively provided with reliefs in correspondence of said first and of said second level, for cooperating alternatively with the printing heads of said first and said second printing hammers, means for activating said interposer member for imparting to the portion of said interposed member interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last mentioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 8. Serial on-the-fly printer, comprising a print carriage movable along the print line, for occupying in succession all the possible positions along the print line; a typecarrying member in continuous motion for bringing into print position in succession every character of a character set, mounted on said print carriage; a printing member mounted on said print carriage and comprising a first and a second printing hammer having printing heads superimposed on a first and a second level, said printing heads having a width sufficient to span two print positions; an interposer member, mounted on said print carriage, and having variable portions interposable in succession between said typecarrying member and said printing member, said variable portions being alternatively provided with reliefs in correspondence of said first and of said second level, for cooperating alternatively with the printing heads of said first and said second printing hammers; means for activating said interposer member for imparting to the portion of said interposer member, interposed between the said typecarrying member and said printing member, a motion correlated to the motion of the print carriage and directed in the opposite direction thereto, for maintaining said variable interposed portion in a substantially fixed position in registration with a predetermined print position during the entire interposition interval, said last mentioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 9. A serial printer comprising: typecarrying means movable adjacent a plurality of print positions in a print line, carriage means movable along a line parallel to the print line, printing means disposed on said carriage and comprising at least two printing hammers partially superimposed, interposer means comprising a plurality of portions interposable in succession between said typecarrying means and said printing hammers, and means for imparting a motion to said interposer portion disposed between said typecarrying means and said printing hammer which motion is correlated to movement of said carriage which is in the opposite direction, to said carriage movement for maintaining said interposer portion in a substantially fixed position in registration with a predetermined print position during its interposed interval, said last mentioned means being effective to subsequently bring successive interposable portions between said type-carrying member and said printing member.
 10. The serial printer of claim 9 wherein said typecarrying means comprises a rotating assembly of flexible tongues, each tongue having disposed at its free extremity a chAracter of a character set.
 11. The serial printer of claim 10 wherein said interposer means comprises a rotatable assembly of flexible blades having said portions disposed at the ends thereof, said assembly being located coaxial with said type-carrying means.
 12. The serial printer of claim 9 wherein said printing heads are superimposed as set forth on a first and a second level each head having a width substantially equal to two print positions, and wherein said interposer portions are provided with reliefs in correspondence with said first and second levels for cooperating alternatively with said two printing heads. 